Country-specific crossing presets

[osmuser63783]

Hi, I am opening this issue here to get maintainer feedback before I put in the work to create a pull request.

There are only a few different crossing types in the UK and there’s a desire in the UK community for more specific presets. Mappers take issue with the generic “marked crosswalk” preset which sets crossing:markings=yes. If I type in “zebra crossing” then I should be shown a zebra crossing preset, and that should populate all the right tags.

Now as far as I understand, there used to be a zebra crossing preset that would add crossing=zebra but the US version of iD called it “marked crosswalk”, and the US has all sorts of crossing markings, so this led to the crossing=zebra tag being used, confusingly, for all sorts of marked crossings, whether they had zebra markings or not. I would want to avoid repeating this. 
It seems the solution is region- or country-specific presets.

I brought up the idea in the UK community subform, here and here, and it generally got positive feedback.

If you think this idea is worth pursuing (& has a chance of being merged), then I could start working on a bunch of UK-specific presets that would look a bit like this, but I’d discuss the specific tags with the community. The generic marked crossing preset could even be disabled in the UK.